Evidence for Higgs boson decays to a low-mass dilepton system and a photon in pp collisions at √s = 13 TeV with the ATLAS detector

ATLAS Collaboration

doi:10.1016/j.physletb.2021.136412

Evidence for Higgs boson decays to a low-mass dilepton system and a photon in pp collisions at √s = 13 TeV with the ATLAS detector

ATLAS Collaboration

Physics and Astronomy

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Abstract

A search for the Higgs boson decaying into a photon and a pair of electrons or muons with an invariant mass m_ℓℓ < 30$ GeV is presented. The analysis is performed using 139 fb^-1 of proton-proton collision data, produced by the LHC at a centre-of-mass energy of 13 TeV and collected by the ATLAS experiment. Evidence for the H → ℓℓγ process is found with a significance of 3.2 over the background-only hypothesis, compared to an expected significance of 2.1 for the Standard Model prediction. The best-fit value of the signal strength parameter, defined as the ratio of the observed signal yield to the one expected in the Standard Model, is μ = 1.5 ± 0.5. The Higgs boson production cross-section times the H → ℓℓγ branching ratio for m_ℓℓ < 30$ GeV is determined to be 8.7_-2.7^+2.8 fb.

Original language	English
Article number	136412
Number of pages	22
Journal	Phys. Lett. B
Volume	819
Early online date	31 May 2021
DOIs	https://doi.org/10.1016/j.physletb.2021.136412
Publication status	Published - 10 Aug 2021

Bibliographical note

39 pages in total, author list starting page 23, 5 figures, 1 table, submitted to PLB, All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGG-2018-43/

Keywords

hep-ex

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AadG2021EvidenceFinal published version, 1.75 MBLicence: Creative Commons: Attribution (CC BY)

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title = "Evidence for Higgs boson decays to a low-mass dilepton system and a photon in pp collisions at √s = 13 TeV with the ATLAS detector",

abstract = " A search for the Higgs boson decaying into a photon and a pair of electrons or muons with an invariant mass mℓℓ < 30$ GeV is presented. The analysis is performed using 139 fb-1 of proton-proton collision data, produced by the LHC at a centre-of-mass energy of 13 TeV and collected by the ATLAS experiment. Evidence for the H → ℓℓγ process is found with a significance of 3.2 over the background-only hypothesis, compared to an expected significance of 2.1 for the Standard Model prediction. The best-fit value of the signal strength parameter, defined as the ratio of the observed signal yield to the one expected in the Standard Model, is μ = 1.5 ± 0.5. The Higgs boson production cross-section times the H → ℓℓγ branching ratio for mℓℓ < 30$ GeV is determined to be 8.7-2.7+2.8 fb.",

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author = "{ATLAS Collaboration} and Paul Newman",

note = "39 pages in total, author list starting page 23, 5 figures, 1 table, submitted to PLB, All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGG-2018-43/",

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AU - ATLAS Collaboration

AU - Newman, Paul

N1 - 39 pages in total, author list starting page 23, 5 figures, 1 table, submitted to PLB, All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGG-2018-43/

PY - 2021/8/10

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N2 - A search for the Higgs boson decaying into a photon and a pair of electrons or muons with an invariant mass mℓℓ < 30$ GeV is presented. The analysis is performed using 139 fb-1 of proton-proton collision data, produced by the LHC at a centre-of-mass energy of 13 TeV and collected by the ATLAS experiment. Evidence for the H → ℓℓγ process is found with a significance of 3.2 over the background-only hypothesis, compared to an expected significance of 2.1 for the Standard Model prediction. The best-fit value of the signal strength parameter, defined as the ratio of the observed signal yield to the one expected in the Standard Model, is μ = 1.5 ± 0.5. The Higgs boson production cross-section times the H → ℓℓγ branching ratio for mℓℓ < 30$ GeV is determined to be 8.7-2.7+2.8 fb.

AB - A search for the Higgs boson decaying into a photon and a pair of electrons or muons with an invariant mass mℓℓ < 30$ GeV is presented. The analysis is performed using 139 fb-1 of proton-proton collision data, produced by the LHC at a centre-of-mass energy of 13 TeV and collected by the ATLAS experiment. Evidence for the H → ℓℓγ process is found with a significance of 3.2 over the background-only hypothesis, compared to an expected significance of 2.1 for the Standard Model prediction. The best-fit value of the signal strength parameter, defined as the ratio of the observed signal yield to the one expected in the Standard Model, is μ = 1.5 ± 0.5. The Higgs boson production cross-section times the H → ℓℓγ branching ratio for mℓℓ < 30$ GeV is determined to be 8.7-2.7+2.8 fb.

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DO - 10.1016/j.physletb.2021.136412

M3 - Article

VL - 819

JO - Phys. Lett. B

JF - Phys. Lett. B

M1 - 136412

ER -

Evidence for Higgs boson decays to a low-mass dilepton system and a photon in pp collisions at √s = 13 TeV with the ATLAS detector

Abstract

Bibliographical note

Keywords

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Cite this